Helically-tracking milling assembly with tiltable thread cutting head

ABSTRACT

An assembly for positioning and operating a milling tool or thread-forming rotary cutter, either within or external to a workpiece such as a cylinder or tube, which positioning is of especial value when the workpiece itself is inconvenient to move or rotate due to size or shape. The cutting head can follow a helical path of selected pitch provided by interchangeable pairs of threadedly engaged guide cylinders carried by telescopic members, so as to transfer such thread pattern to the workpiece. By transversely extensible gear means (such as splined shaftbevel gear units or split gear trains) a transverse carriage which carries the cutting-positioning head can adjust the latter to different internal or external radii of the workpiece. In addition, by adjustable tilting of the positioning head, it can carry a rotary cutter of smaller diameter and hence greater cutting force; such head can be set at any angle within 360* rotation from the axis of the transverse carriage. Thus the rotary cutter can be set to the same inclination as the track of the thread being cut. The direction of rotary drive can be completely reversed, i.e., 180*. As one power source, the positioning assembly can be attached to a milling machine, or it can be operated independently thereof.

United States Patent Escobedo Sept. 12, 1972 [54] HELICALLY-TRACKINGMILLING ASSEMBLY WITH TILTABLE THREAD CUTTING HEAD [72] Inventor:Francisco Calif. 90303 [73] Assignee: Fresco Industries, Inc., Gardena,

Calif. [22] Filed: April 29, 1970 [211 Appl.No.: 32,805

Related US. Application Data [63] Continuation-impart of Ser. No.731,494, May

23, 1968, Pat. No. 3,526,167.

Escobedo, lnglewood,

Primary Examiner-Gil Weidenfeld Att0rneyHoward L. Johnson ABSTRACT Anassembly for positioning and operating a milling tool or thread-formingrotary cutter, either within or external to a workpiece such as acylinder or tube, which positioning is of especial value when theworkpiece itself is inconvenient to move or rotate due to size or shape.The cutting head can follow a helical path of selected pitch provided byinterchangeable pairs of threadedly engaged guide cylinders carried bytelescopic members, so as to transfer such thread pattern to theworkpiece. By transversely extensible gear means (such as splinedshaft-bevel gear units or split gear trains) a transverse carriage whichcarries the cutting-positioning head can adjust the latter to differentinternal or external radii of the workpiece. In addition, by adjustabletilting of the positioning head,

it can carry a rotary cutter of smaller diameter and hence greatercutting force; such head can be set at any angle within 360 rotationfrom the axis of the transverse carriage. Thus therotary cutter can beset to the same inclination as the track of the thread being cut. Thedirection of rotary drive can be completely reversed, i.e., 180" As onepower source, the positioning assembly can be attached to a millingmachine, or it can be operated independently thereof.

8 Claims, 51 Drawing Figures sum as or 12 m mm M N m i a x 1|. @w i K W& um w M NN PMENTEnsEP 12 1972 SHEET OBUF 12 F M 25! Z60 I N VE N TOR.IkA/vr/sm Beau-w BY PATENTEnsEm m2 SHEET 12 0P 1.2

l NVEN TOR. EQA NC/560 E'COBEDO BY TTOF/VE) BRIEF DESCRIPTION OF THEINVENTION piece or within a cylindrical bore. The pitch of the formedthreads is the pitch of the selected pair of interchangeable,cylindrical guide sleeves which are inserted within a telescopic columnof the structure. The present invention adds to this basic construction,a drive train for further laterally offsetting the cutter and forreversing its axial orientation 180, in association with means forselectively tiltingthe cutting head so that the head may conform to theslant or inclination of the thread being cut. Thus square threads orbuttress threads can readily be cut by'having the rotary cutting headslanted to the angle of the helix. Previously such threads were cut bymounting the workpiece on a lathe in axial alignment with the driveshaft of the (prior art) cutter and then rotatingthe lathe. Now this isno longer necessary. workpieces of unsymmetrical shape or too large tobe rotated can have a bore threaded while they remain stationary.

The present tiltable head which carries the rotating cutter may be setat any rotational position through 360. In addition, the direction ofdrive can be reversed 180". One construction for the present drive trainattaehment is shown in FIGS. -32 and comprises a longitudinally movable,externally splined shaft which is driven by a pair of bevel gears fromthe axially displaceable drive stem, one of the bevel gears having atubular, longitudinally ribbed or internally splined shaft in which theexternally splined shaft is slidably received. The distal end of theslidable shaft is journalled within a hollow cubical, head unit where itcarries a bevel gear which ultimately drives a cutter-carrying spindle,the head being pivoted for positional setting about the axis of thebevel gear. The head can thus be set at any desired angle of rotation soas to slant the cutter relative to the helix which it is forming on theworkpiece.

Another construction for achieving a comparable result is shown in FIGS.33-51 whereby the tiltable positioning head can be disposed within abore with its direction of drive inverted 180 and the cutter theninclined that it cuts a thread having a plane perpendicular to the bore.Such a construction begins with the previous rotatable housing havingits split-trio gear train. The housing carries a transversely slidableundercarriage which is (calibratedly) movable with the scissors actionof the gear trio. A projecting end of the housing carries a tiltablepositioning head by which the ultimate cutter spindle can be set at anyselected angle.

Thus by use of the telescopic unit and interchangeable pairs ofthreadedly engaged guide cylinders, and with various gear extensionmeans for the transverse carriage, there is provided an adjustablehelical tracking assembly which projects a rotary cutter, the

path of which is not dependent on the drive means employed for thedistal rotary cutter.

DESCRIPTION OF THE DRAWINGS FIG. 1 is an axial sectional view of mymilling head, with some portions broken away and some parts shown inelevation.

FIG. 2 is a top plan view as seen along the line 2-2 of FIG. 1.

FIG. 3 is an elevational view as seen along the line 3-3 of FIG. 2, witha portion broken away to show a lock pin.

FIG. 4 is a bottom plan view as seen along the line 4-4 in FIG. 1.

FIG. 5 is a transverse sectional view taken along the line 5-5 of FIG.I, and particularly showing the adjusting screw and slide block.

FIG. 6 is a transverse sectional view taken along the line 6--6 of FIG.1, showing the locking elements in broken lines.

FIG. 7 is a detail view through the gear housing, taken along the line7-7 of FIG. 5, and showing the locking elements in elevation.

FIG. 8 is an axial section through the gear housing taken along the line8-8 of FIG. 5, with parts in elevation.

FIG. 9 is an elevational view of a portion of the gear housing, showingthehead of the adjusting screw as seen along the line 9-9 of FIG. 5.

FIG. 10 is an axial section taken through the drive stem (seen inelevation) and particularly showing (in place of the threaded guidecylinders of FIG. I) a pair of unthreaded cylinders which prevent axialseparation or spiral movement of the drive shaft and driven shaft.

FIG. 11 is a top plan view of a workpiece, showing a cutter used withthe threaded guide cylinders of FIG. I to form interrupted threads intwo adjacent bores of a workpiece.

FIG. 12 is a transverse sectional view taken through the workpiece ofFIG. 11 along the line l2-- I2.

FIG. 13 is an elevational view of the upper portion of the milling head,partly broken away or in section, which head has been modified byincorporation of a hand-crank for rotationally positioning the drivenend.

FIG. 14 is a transverse sectional view taken along the line 14-14 ofFIG. 13.

FIG. 15 is a transverse section through an annularly drilled andcentrally threaded workpiece, showing how two different groove-cuttingtools may then be used with the present head, respectively to cut a sidegroove and to mill a bottom channel.

FIGS. 16 and 17 are, respectively, top and vertical sectional views of aworkpiece showing how a fly cutter can be used with the present head toshave or level the top surface of a workpiece.

FIG. 18 is a plan view of a head gasket for a single cylinder of anengine, which gasket can be formed in such configuration from sheetmetal by the present milling head.

FIG. 19 is an axial sectional view through the gear housing, with partsin elevation, and particularly showing a modified construction of shiftblock for the gear train mounted thereon.

FIG. 20 is a transverse sectional view taken along the line 20-20 ofFIG. 19, with the gears in position to 3 tiagmit rotary motion to aconcentrically disposed s FIG. 21 is a similar view with the gears inposition to drive an offset shaft.

FIG. 22 is an axial sectional view of an adapter unit shown attached tothe head of FIG. 19.

FIG. 23 is a transverse section taken along the line 23-23 of FIG. 22.

FIG. 24 is a similar view along line 24-24 of FIG. 1, of an adapterattached to the head of FIG. 1 (with the cover plate 85 removed).

FIG. 25 is an axial sectional view similar to FIG. 1 but with a modifieddriveand positioning-assembly coupled to the drive shaft of the millingmachine, with the possible lateral and axial projections indicated inphantom.

FIG. 26 is a transverse section taken along the line 26-26 of FIG. 25and particularly showing the manually operable worm gear used to obtainspiral movement of the outer gear housing relative to the inner housing.

FIG. 27 is a bottom plan view of the construction of FIG. 25 with partsbroken away.

FIG. 28 is an elevational view of the lower portion of FIG. 25 as viewedalong the line 28-28.

FIG. 29 is similar to FIG. 28 but with the head rotated 90 in thedirection of the arrow.

FIG. 30 is an axial sectional view taken along the line 30-30 of FIG.25, particularly showing the lock mechanism.

FIG. 31 is a sectional view taken at right angles to FIG. 30 along theline 31-31.

FIG. 32 is a staggered transverse section taken along the line 32-32 ofFIG. 31.

FIG. 33 is a longitudinal axial section, partly in elevation, of anothertiltable head construction.

FIG. 34 is partially a plan view and partially a transverse section, asviewed along the line 34-34 of FIG. 33.

FIG. 35 is a side elevational view of the lower portion of FIG. 33 asviewed from the rear of FIG. 33, or as seen from the left side of FIG.38.

FIG. 36 is a fragmental elevation of the right side of FIG. 38.

FIG. 37 is an end elevational view as seen from the left of FIG. 35.

FIG. 38 is an elevational view of the opposite end of FIG. 37.

FIG. 39 is a sectional view taken along line 39-39 of FIG. 38 andshowing the tapered adjustment wedge.

FIG. 40 is a transverse section along line 40-40 of FIG. 33.

FIG. 41 is a transverse section taken along line 41- 41 of FIG. 33.

FIG. 42 is a bottom plan view of FIG. 35 on a smaller scale.

FIG. 43 is a transverse axial sectional view taken through the lowerportion of FIG. 33 at right angle thereto, with portions in elevation.

FIG. 44 is a sectional view taken along the line 44- 44 of FIG. 43.

FIG. 45 is a sectional view taken along the line 45- 45 of FIG. 43.

FIG. 46 is a sectional view taken along the line 46- 46 of FIG. 43.

FIG. 47 is an enlarged detail in axial section, showing adjacent shaftends which carry the first and last gears of the split-trio gear train,the transverse center line of this figure corresponding to the uppersection line of FIG. 43.

FIG. 48 is an axial sectional view taken at right angle to FIG. 43,partly in elevation, with the undercarriage at its extreme leftposition.

FIG. 49 is a transverse sectional view taken along the line 49-49 ofFIG. 48.

FIG. 50 is a transverse sectional view taken along the line 50-50 ofFIG. 48.

FIG. 51 is a schematic view of the position taken by the cutter of FIGS.35-50 in cutting buttress threads.

DESCRIPTION OF ONE EMBODIMENT As seen particularly in Figs. 1-3, thestationary or upper housing member 20 of my milling head attachment isformed as a tube or collar, longitudinally split at 21, and in mountinghas its adjacent side edges drawn together and clamped tight about thequill 22 of a milling machine (not shown) by means of a pair of radiallyoutwardly projecting shoulders 23, 24, which are selectively heldtogether by pull screws 25, 26. One-half of the housing tube 20 ispermanently fixed to the underbody by lock pins 18, 19 (FIGS. 2,3).Along one side of the housing, a thumb screw 27 is received in a tappedaperture 28 after passing through a longitudinal slot 29 of an L-shapedstop member 30 which is thus adjustably positioned and held against theouter face of the housing at any desired position along the length ofthe slot, for a purpose detailed below.

Concentrically centered within the housing 20 and quill 22, theconventional draw bar 31 and collet 32 of the milling machine spindle Spare coupled to an axially movable stem or drive shaft 33 of the adapterby means of a sleeve 34 which carries a row of hardened pins 35,36,37,having their inner ends riding in a longitudinal slot 38 of the stem 33.The coupled shaft or stem 33 is thus rotated in unison with the sleeves34, collet 32 and spindle Sp, but due to the slot or guideway 38, thestem 33 can move lengthwise at the same time, the pins 35, 36, 37 actinglike a key.

The upper housing 20 dependently carries an intermediate housing forrnedof a concentric pair of tubular "telescopingcylinders, the inner one 39of which is fastened to the upper housing by a circle of screws 40. Theouter cylinder 42 is lengthwise and rotationally slidable about theinner cylinder 39 and is formed with an upper, outward-projecting ledge43 which is positioned for abutment with the intumed arm 44 of the L-shaped stop 30. A lower terminal ledge 45 of the outer cylinder isfastened to a loweror gear-housing 46 by a circle of screws 47.

Within the open center 49 of the inner telescoping tube 39, aninternally threaded guide cylinder or insert 50 is removably mounted bymeans of a circle of screws 51 inserted jointly through a top flange 53of the insert 50 and through an inwardly projecting shoulder 54 of theinner tube 39. An externally threaded guide cylinder or insert 55(having threads of the same pitch as those of the insert 50) has a lowerflange 56 fastened to the top of the housing plate 57 by a circle ofscrews 58. Access to these last screws for a manipulating tool is by wayof a corresponding circle of openings 60 in the flange 53 of the innerinsert 50.

. I At its lower or distal extremity, the drive stem 33 traverses abearing collar 62 and has its end fixed to a cylindrical gear wheel 63which is thus centered within the annular chamber 64 of the rotatablegear housing member 46. Slidably movable transversely (i.e., in adiametric plane) within the chamber 64 is a shift elea bored stem 68which is journaled between lower 69' and upper 70 bearings within turret66. A drive shaft 71 for a cutter 72 or other rotary tool is detachablyheld in the bore of the spindle 67 by a set screw 73. Proximately, thehub or reduced end of the socketed stem 68 fixedly carries a cylindricalgear 75 which is thus paired in size and direction of rotation with thegear 63 which is from time to time directly (that is, concentrically)above it within the block 65, the gear 75 thus being retained in a lowersocket or cavity of the slide block 65.

The slide block 65 is formed with an upward-opening, multi-level cavity76 (FIG. 1), and is pivoted on a stub shaft 77 which carries anintermediate gear 83 which is equal to the axial thickness or height ofboth members of the pair of gears 63, 75 and engages both of them at alltimes so as to transmit rotary drive (in the same direction) from thestern gear 63 to the ultimate drive gear 75. However, depending upon theposition of the slide block 65 which swings transversely on the shaft oraxis of the intermediate gear. 83, the paired gear 75 is selectivelyaxially aligned or disaligned with its corresponding gear 63; thiscorrespondingly aligns or disaligns the ultimate drive shaft 67 (71)with the stem 33 and driving shaft Sp. The upper gear 63, however,remains at the same location within the housing 46, regardless of shiftsof the lower gear 75 by the slide block 65, but its position within thecavity of the slide block changes. The stub shaft 77 which in effect isthe pivot for shift of the gear 75 relative to gear 63, is journalled inthe three bearing assemblies 78, 79, 80.

Looking at it in another way: the intermediate gear 83 has an axialheight of two units" and is retained in a corresponding cylindricalportion of the cavity 76 by the stud shaft 77. The permanently locateddrive gear 63 projects into an adjacent cavity area 760 (FIGS. 5 and 8)of one unit" height but of greater lateral width than the drive gear. Inshifting of the slide block 65, these two engaged gears 83 and 63 retaintheir positions within the housing 46, but the slide block while itembraces or contains them, also moves in relation to them andtransversely carries the third engaged gear 75 which is retained in acavity of one unit" height in the block, which last cavity portionclosely surrounds the gears. Thus, in moving, the slide block carriesthis lower gear 75 with it, that is, from a concentric position directlybeneath the drive gear 63, to a position '1 76a, which is moved sidewisein respect to the stationary drive gear 63. A somewhat larger, ovalopening 84,

corresponding to the just-mentioned slide block cavity, when the latteris in concentric position, is formed in the housing end plate 81, andallows the projecting turret 66 to move sidewise in this opening withmovement of the slide block (FIGS. 5-6). A cover plate 85, having acollar 86 secured to the turret by screws 48, is slidably disposedoverlying this opening 84, upon movement of the turret 66 (FIG. 1). Theend plate 81 is fixed to the housing 46 by a circle of screws 82 (FIG.4).

One apical end of the slide block 65 is formed with a transverse channelor slot 87 (FIGS. 1 and 5), disposed generally parallel to the top andbottom faces of the block, and the block is also drilled to form acylindrical opening 88 which traverses the axial thickness or height ofthe block. A flat-ended, cylindrical plug 89 is rotatably disposedwithin the cannel 87 with its ends flush with the corresponding outerfaces of the block 65. An elongated screw 90 is inserted through anopening 91 of the annular housing 46, with its inner end receivedthrough a tapped, diametric opening 92 of the plug 89. Adjusting screw90 is formed with a flared head 93 bearing calibrated measurementindicia, and having an annular groove 94 surrounding its shank, whichgroove receives a fixed pin 95 (FIG. 5) along one side after insertionthrough the wall 46, thus preventing longitudinal movement of the screw.Accordingly, rotation of the screw 90 in one direction or the other,will move the threadedly engaged plug 89 lengthwise along the screweither toward or away from the head 93, and thus slide the block 65 inthe same direction while it remains sandwiched between the top 96 andbottom 97 faces of the chamber 64. As explained earlier, this locatesthe dependently projecting turret 66 and cutter shaft 71 at the desiredeccentric position relative to the upper shafts 33, 31.

Lock means are also provided to hold the slide block at any suchselected location. A right-angled passage 98 (FIGS. 5,6,7) is formed inthe end plate 81 horizontally underlying the slide block 65; twocylindrical pins 99, 100 having complementary (45) angled engagingend-faces 101 are housed lengthwise-slidable in the respective channelportions. A set screw 102 is located in an outer tapped section 103 ofthe passage, such as a socket-head screw which is readily operable by atool (not shown). Accordingly, small rotation of the screw 102 serves topush the pin 100 lengthwise inward and this raises the mating pin 99perpendicularly upward so as to abut or frictionally engage theunderface of the slide block 65 and prevent its further movement withinthe chamber 64.

In the construction detailed in FIG. 10, the cylindrical pair ofthreaded sleeves or inserts 50, 55 shown in FIG. 1 are replaced byunthreaded inserts 104, 105 which are locked together for relativeannular movement by ball-bearing raceways 106. Accordingly, the twoinserts do not move axially with respect to each other. Such inserts areused, for example, when cutting a single groove 107 in the side of abore, as with the key cutter 108 of FIG. 15. Rotation of the outercylinder 42 now serves merely to move the eccentric turret 66 and itsparticular cutter (108) around the bore 109 of a workpiece, but alwaysat the same height.

The construction illustrated in FIGS. 13-14 provides a hand-crank unitfor rotating the lower housing (42,46) and cutter (108,72) up or down(relative to the fixed upper housing 20, and consequently to a workpieceW) when using the pair of threaded inserts 50,55, or at a constant levelwhen using the unthreaded inserts of FIG. 10. An upper flange of theouter cylinder 42a is formed as a bevel gear 110. A rectangular mountingframe 111 is attached to the housing by a split collar 112 which isloosely retained in an annular groove 113 by a pair of screws or bolts114. A radial shaft 115 journaled in bearings 116, 117 disposes a pinion118 in driving engagement with the bevel gear 1 10. The frame 1 11 isretained within a rectangular yoke 119 to permit its movement axial tothe shafts 33,31 and also to furnish limit means similar to that of theabutment arm 44 of FIG. 1, the pinion shaft 115 being operated by acrank or hand wheel 120 (or with a drive motor if desired). Without suchcrank assembly, the adapter head can of course be turned by manuallygrasping the tube 42 or the gear housing 46. However, in either case, itwill be observed that the lower housing (42,46) need not be turned at aconstant speed, and its direction may be reversed at will (or stopped)in its travel along the spiral path which is determined by the threadsof inserts 50, 55. This does not alter the constant rotation of thecarried cutter 72, 108, however.

The outer face of tube 42 is provided with an encircling band of angularindicia S (FIG. 13) to indicate the arcuate distance through which thelower housing 46 (and its dependent cutter 72) is rotated.

In the construction of FIGS. 19-21, the drive stem 33 has its lower endjournaled in the bearing raceway collar 62 as before, and thenterminally attached to a cylindrical gear 142 which engages a laterallyadjacent gear 143 which is carried on a stub shaft 144 having its upperend received in a cross bearing channel 196 of the top plate 57a of thegear housing. The pivot shaft 144 traverses bearing assemblies in aflat-faced pair of juxtaposed slide plates, or links 145, 146 and hasits lower end fixed to a gear 147 which engages a shiftable gear 148(similar to gear 75 of FIG. 1) which shiftable gear is carried on thereduced end 74a of the driven shaft 67a. The end 74a extends upwardsinto a rotary bearing unit 149 of the lower link 146 while thecorresponding end 150 of the drive stem 33 extends downward into abearing unit 151 of the upper link 145. The two juxtaposed link plates145, 146 are formed with mating surfaces designed for limited rotationalmovement about the axis of the stub shaft 144, by reason of a downwardprojecting, arcuate ridge or shoulder 152 (FIG. 19) of the upper platewhich seats in a corresponding groove of the lower plate. Accordingly,the link plates and their connected drive shafts 33, 67a can be movedtogether or separated like the blades of a pair of scissors which arepivoted on the axis of the shaft 144; such movement serves to axiallyallign (FIG. 20) or offset (FIG. 21) the two shafts 33, 67a (71) whiletheir drive connection is maintained at all times through the geartrain. The lower link 146 thus takes the place of the socketed lowerportion of the earlier slide block 65, which journals the two gears 75,83 of FIG. 1. The upper link 145 takes the place of the housing plate 57which journals the two gears 63, 83 of FIG. 1. The difference is that inthe FIG. 19 case, the shafts of the two gears are shiftable instead ofjust one (74 in FIG. 1). In other words, the shaft 144 of theintermediate gear (now split into two fragments 143, 147) is now madeshiftable while still serving as a pivot point. Consequently thecorresponding slide block (158) can be moved in a straight line insteadof arcuately as was necessary with the block 65. To aid in returning thegear train to concentric drive position (FIG. 20) from offset position(FIG. 21), a tension spring 194 connects a lateral ear 195 of the upperlink plate with a lug 193 on the inner face of the gear housing 46a.

The bottom plate 81a of the gear housing is formed with two upwardextensions 153, 154 having their upper arcuate edges lodged beneathcorresponding shoulders 155, 156 of the inner housing side wall and withmutually facing, inner beveled edges jointly forming a transverse ordiametric channel 157 across the floor of the housing. A pair ofcorresponding angled, elongated, rectangular gibs 160, 161 line thesides of the channel. The top of the turret 66a is formed with awedge-shaped projection 158 which is shorter than and slidablelengthwise along the channel which it contacts on both sides; the wedgecarries a bearing unit 159 which journals the socketed stem 680 whichthe latter upwardly terminated in the reduced end 74a which carries thegear 148. Accordingly, as the wedge 158 is moved back and forth alongthe channel 157, it correspondingly locates the turret 660 along thelength of the oval bottom opening in the plate 81a through which theturret projects. This shifts the driven shaft 67a between axialalignment with the drive shaft Sp, 33 (the position of FIG. 20) and theoffset position of FIG. 21. The wedge 158 is locked in any such selectedposition by means of a screw 162 which is received through a bore 163 ofthe side housing 172 and threadedly engaged in a tapped opening 164 ofthe projection 154, with its inner end in frictional abutment with aledge of the gib 161. An adjusting screw 166 has its head 171 rotatablyseated in a recess 167 of the housing side wall 172 and there anchoredagainst axial displacement by a pin 168 (FIG. 20) inserted through avertical bore and lodged in an annular groove 173 formed around the neckof the screw. The inner end of the screw is received in a radiallydirected, tapped bore of the sliding wedge 158, which bore is parallelto the sides of the slide channel 157.

FIGS. 22-23 show an adapter unit for positioning the driven shaft (67a)at a further offset position from the initial drive shaft (Sp, 33) whichadapter may thus be used in order to position a cutter to cut largediameter openings, grooves, threads, scallops, etc. The cover 85a ofFIG. 19 is first removed and to the nonrotating turret 66a, there isaffixed a partially open-top housing tube 175 having a top flange 176formed with a pair of parallel slots 177, 178 disposed to receiveattachment bolts or screws 179, 180 for coupling it to the underface ofbottom plate 81a. Split wings 181, 182 along one side of the housing areprovided with transverse, threaded fasteners 183 for drawing the partstightly together Within the housing, a spindle 184 has its upper endfixed in the rotary socket 68a and distally carries a gear 185 with thespindle end being journaled in bearing unit 186. A parallel spindle 188having its ends journaled in bearing units 189, 190 carries a gear 187which is driven by gear 185 and disposes a socket 191 and set screw 192for anchorage of the shaft of a selected cutter.

A similar adapter unit (FIG. 24) is provided for attachment to thebottom of the head of FIG. 1, upon removal of the cover plate 85. Theflange plate 197 is secured to the underface of housing plate 81 bybolts 201, 202 inserted through curved slots 199,200. These are locatedto allow pivoting of the flange 197 about the point 198 (beforetightening the bolts 201, 202) so as to accommodate to a particularoffset position of the projecting turret 66.

By having the workpiece on a milling table (not shown) the table can beused to raise or lower the workpiece and thus permit cutting grooves atdifferent heights. By use of an end mill 121 (FIG. bottom grooves 122can be cut; or with a fly cutter 123 (FIG. 16-17) an uneven surface canbe leveled or shaved, either by moving the rotating cutter in a largeenough circle to sweep the workpiece, or by moving the workpiece bymeans of the milling table.

I As further illustrative examples of usage of my composite millinghead: The head gasket G of FIG. 18 can be formed on a milling table.With the cutting end 121 of FIG. 15, the central annulus 124 is removedand the concentric cuts a, b, c, d, are made, in each case with thedriven shaft v71 disposed at a circumference of a circle based on thepoint 125 which corresponds to the central axis of shafts 31, 33; thisis when using the pair of non-spiral guide inserts of FIG. 10 (104,105). The four cutouts 126, 127, 128 and 129 are similarly drilled orcut (depending upon their size) by radiusing the cutter from thecorresponding centers. In such manner, scalloping or profiling ofnumerous workpiece intended for various specialized uses can be made.Straight cuts can be made simply by moving the milling table in astraight line, without arcing the cutter shaft 71. But any desiredradius for a curved cut can be quickly set, simply by adjusting theoff-center position of the turret 66 by means of the slide block 65,positioning screw 90 and lock 99, 100, 102 of FIG. 1; or by setting thesliding wedge 158 of FIG. 19. However in making such cuts with an endmill 121, the spiral guide inserts 50, 55 need not be replaced by thenon-spiral inserts 104, 105, since a simultaneous small axialdisplacement of the cutter would be immaterial. For larger diameter arcsor circles, the adapters of FIGS. 2224 are used.

Use of a thread cutter72 with the present milling head is particularlyeffective in cutting interrupted threads (FIGS. 11-12) in intersectingbores 139, 140, since the vertical margin 41 of the two bores does notresult in a jagged or torn edge as may be the case when using aconventional tap. Likewise, the problem of supporting such tap inthreading an interrupted bore does v not arise with the present cutter.

DESCRIPTION OF SECOND EMBODIMENT .axial collet 32a, sleeve 34a and thelongitudinally movable drive stem 33a. Distally the fixed cylinder 39asupports a threadedly engaged pair of guide cylinders 50, 55, the formerbeing fixedly secured to the cylinder 39a by a circle of screws 51. Theinner guide cylinder 55 is distally secured to the rotatable gearhousing member 46a by an inner circle of screws 58a. An outer housingcylinder 42a which movably embraces the fixed cylinder 39a, isterminally fastened to the gear housing by an outer circle of screws47a, and proximately carries an external ring gear 205 pinned thereto,which ring gear engages a worm gear 206 on a drive shaft 207 which maybe operated manually by a hand wheel 208, or mechanically if preferred.

Axially spaced apart along the outer telescopic cylinder 420, are anabutment flange 209 and an annular band or ring 210 pinned to thecylinder 42a; between the flange and band, an encircling L-shaped collar212 supports the worm gear housing 211, being separated from therotatable cylinder 420 by a thrust bearing B. The collar 212 is axiallyslidable along the lengths of a parallel pair of distally headed, guidepins 203, 204 (FIG. 26) which have their proximate ends fixedly securedto the attachment flange'of the fixed, inner housing tube 39a. The outerhousing 42a thus can move lengthwise to the pins 203,204 without itrotating; at the same time, the outer housing 42a may be rotated byaction of the worm gear 206.

As in the previous embodiment, the inner guide cylinder 55 itself isspirally movable by its rotation about the threads of the outer cylinder50 (simultaneous with rotation of telescoping outer cylinder 420 whichis bolted thereto at 580). In order to accommodate such axialseparation, the drive sleeve 34a is longitudinally slotted at 213 andreceives a cross pin 214 therein which projects from the drive stem 33a.It will be seen that the spindle 22a, collet 32a, sleeve 34a and drivestem 33a all rotate in unison; but at the same time the drive stem canmove lengthwise as made possible by the longitudinal separation orconvergence of the telescopic tubes 39a and 42a, which movement iseffected by the rotation of the threaded guide inserts 50, 55. Suchaxial separation and convergence is governed by the rotation of wormgear 206, which at any desired point can be reversed or held stationaryat will. Meanwhile the cutter (72) continues to be driven from themilling machine by the revolving drive stem 33a and the subsequent geartrain.

The distal end of the drive stem 33a traverses a pair of bearingassemblies 215, 216, which are at opposite ends of an aperture 226 ofthe housing wall 57b, the drive stem carrying lock collar 267 with setscrew and terminating in a bevel gear 217 in cavity 89a, engaginganother bevel gear 218, at right angles thereto. The latter is formedintegral with an internally ribbed sleeve 222 which embraces a splinedshaft 219. The rotatable sleeve 222 is positioned by a lock nut 225 andthrust bearing mounted on its threaded end 227, the sleeve and gear 218being thus joumaled by the bearing assemblies 223, 224 which are locatedin a downward projection 268 from the housing wall 57b. It will thus beseen that the shaft 219 is movable lengthwise (between the positions ofFIG. 25 and FIG. 31) at the same time that it is being rotated by thesleeve 222, as

the latter is driven by the bevel gear 217.

The transverse chamber 89a of the gear housing 46a is open at one side(to the right in FIGS. 25, 27, 31) and ispartially closed at the end orbottom by the plate 228 which is secured by screws 229, 230. Within theii. i

chamber is a longitudinally slidable frame F, formed of parallel sidewalls 231, 232 upstanding from a base 233 which is characterized by aprojecting guide rib 234, 235 extending wedge-shaped along each side ina corresponding track or guideway of the housing 46a. Each upstandingside wall 231, 232 is formed with a closedend slot 236, 237 throughwhich a limit pin 238 is jointly inserted, with its head 239 lodged inan external recess 240 of the housing, and its distal, threaded endreceived in a tapped aperture 241 (FIG. 30). The possible distance oftravel of the frame F is thus equal to the length of the pair of slots236, 237. Lengthwise positioning or adjustment of the frame F along thechamber 890 is effected by a screw 242 which traverses the housing walland is received in a threaded bore 243 of the base 233, being heldagainst longitudinal displacement by a lock ring 244 (FIG. 25) withinthe housing. Accordingly, rotation of the screw 242 by a suitable toolapplied to the external (slotted or socketed) head 245 serves to movethe frame F toward or away from the head of the screw.

At the inner end of the sliding base 233 is a perpendicular end wall 246which connects the parallel side walls 231, 232 of the frame F andextends thereabove within a cavity 247 (FIG. 31) of the housing. The endwall 246 is centrally traversed at 221'by the splined shaft 219, with abearing ring 248 on its inner face sandwiched by a pinned collar 220 ofthe shaft 219. Outward or distally, the shaft 219 powers an adjustablehead H and terminates in a bevel gear 249 therein.

The construction of the head H is based on a mounting plate 250 which isjuxtaposed against and is rotationally adjustable relative to the outerface of the end wall 246 of the frame F. The plate 250 is traversed bythe distal end of the splined shaft 219 and has a bearing assembly 251for the shaft, inset in the plate. Lateral strips along two opposingedges of the plate are formed each with an arcuate slot 252, 253 whichoverlie a circle of (twelve) threaded sockets X (FIGS. 28-29), of whichany diametric pair of said sockets receive a pair of bolts 254, 255which are inserted successively through lock washers 256, 257 (FIG. 32)and through the slots of the plate. Accordingly, by deliberate selectionof a particular pair of sockets X and further positioning of the arcuateslots 252, 253 relative thereto, the plate 250 (and head 1'!) can besecured by the bolts 254, 255 at any desired location through 360rotation, thus slanting the spindle 67a (and its cutter 72) at anyselected angle.

The head construction H is completed by rectangular-forming walls 258,259, 260, of which two are apertured and carry bearing assemblies 261,262, and the other one is tapped and closed with a threaded plug 263. Astub shaft 264 extends through the pair of hearing assemblies andcarries a bevel gear 265 which is driven by the bevel gear 249 of thelongitudinally-extensible shaft 219. A cap screw 266 is threadedlyreceived in one end of the stub shaft 264, and the opposite end of theshaft is formed by the spindle 67a having an axial bore 68a and a setscrew 730 by which to mount a drive shaft and cutter as shown in FIG. 1.

DESCRIPTION OF ALTERNATE CONSTRUCTION The construction of FIGS. 33-51has a fixed member or inner telescopic cylinder 39b which from anannularly flared, attachment plate 270 dependently disposes a circle ofterminally flanged, suspension bolts 272, each having their upperextremity 273 threaded and anchored by a nut 274 located in a socketrecess 275 of the plate. An encircling retainer band 276 is apertured at277 for sliding insertion of the respective suspension bolts 272 and inan inner annular recess 278 positions a ring gear 279 which is outwardlysecured to the outer telescopic cylinder 42b. At one side the ring gearis engaged by a worm gear 280 (FIG. 34) which is lodged in a laterallyprojecting housing 281 and carried by an operating shaft 282 which canbe manipulated in either direction by a handle 283 so as to rotate theouter telescopic cylinder 42b. As in the previous construction, theinner face of the retainer band is separated from the outer cylinder 42bby a thrust bearing B, the lower end of which rests on a protrudingannular ledge 285 of the cylinder. The whole assembly may be fastenedonto the end plate of a milling machine by bolts inserted through thecircle of openings 284 of the attachment plate 270. The outer telescopiccylinder 42b may carry an internal bearing sleeve 286 which is insliding contact with the inner cylinder 39b.

Internally or axially, the telescopic cylinders are coupled together bya threadedly engaged pair of guide cylinders or inserts 50a, 55a, thepitch of which determines the spiral movement which the outer cylinder42b follows relative to the inner cylinder 39b in response to actuationof the ring gear 279 by the worm gear 280. As in the earlier forms, themating pair of guide cylinders may be removed and replaced by a similarpair having threads of another pitch, by withdrawal of the circle ofscrews 288 (for the fixed guide cylinder 50a) and 289 (for the movableguide cylinder 55a) FIGS. 33-34.

The axially movable drive stem 33b (fastened to the spindle of a millingmachine as in FIG. 1) distally is journalled in two axially spaced, ballbearing assemblies 287, 290 (FIG. 33, 43) between which it carries agear 291. The latter is the initial or drive unit of a splitintermediatetrio or gear train (291, 292a, 292b, 293) which is arranged for theearlier noted scissors action while maintaining continuous transmissionof the rotary drive to the ultimate driven gear 293 of the trio; in thepresent instance, shift of the third gear being effected in a straightline by calibrated movement of the undercarriage C.

The laterally projecting body of the rotatable housing member 46b isfastened to the bottom of the rotatable tube 42b by a circle of screws314 (FIGS. 43, 44) and dependently carries a transversely adjustableundercarriage C of generally rectangular shape. The two upper,longitudinal edges of the carriage C are each formed with a converginglydirected or angularly inslanted, attachment shoulder 294, 296 (FIG. 37)which are retained longitudinally slidable in corresponding slideways ofchannels 295, 297 of the opposite sides of the gear housing 46b andfastened by set screws 301 (FIG. 43). In assembly, a tapered wedge 300which serves as a bearing surface is inserted along one slideway 297 andsecured to the shoulder 296 by a washer-retaining screw 298, 299 at eachend (FIG. 39).

A shallow longitudinal slide channel 304 is formed in the underface ofthe housing 46b and receives a flat slide plate P having an openovalcenter 333. The plate serves as a grease seal for the chamber aboveit. A hottom-opening, longitudinal slot 302 in the top of the slidechannel, receives-a stop pin- 303 (FIG. 40, 43) upstanding from theslide plate P, so as to provide limits of travel of the slide in each.direction with movement of the undercarriage. The upper face of thecarriage C is also formed with another open-top rectangular channel 305(FIGS. 43, 44) which houses a longitudinally tapped block or nut 306having an upward-projecting portion received in a socket 308 of thehousing 42b and. anchored by a screw 309. A longitudinal positioningscrew 310 is threadedly received through the nut 305 with socketed head311 disposed at an end-face3l2 (FIG. 37) of the carriage and thererestrained against longitudinal movement. Accordingly, the positioningscrew 310 can be rotated in either direction by a wrench (notshown)iinser ted into its end socket 313,. thereby sliding theundercarriage C in one direction or the other along the underface of thegear housing 42b. Calibration indicia around the end face 311 of thepositioning screw provide a gage of the linear movement of the carriageand enable its subsequent return to any previous setting. a

The two intermediate gear portions 292a and 2921) are fixedly connectedto the movable shaft E, the upper cap 316 of the latter being slidablealong an arcuate guide slot H1 (FIG. 45) in extension and retraction ofthe gear train. A mounting nut 317 is on the bottom threaded end of theshaft E. The two portions of the diametrically split, intermediate gearare on opposite sides of a rotatable plate 368 which is retained in theannular housing 42b by a snap ring 369. The plate is axially aperturedat 367 for insertion of the respective shaft end screws 365, 366 (FIG.47) but no shaft traverses the aperture. However, the plate is traversedoffcenter by the shaft E, and a link plate 370 is juxtaposed against itsunderface. The link plate is restrictedly rotatable jointly about adependent boss 371 of the rotatable plate 368 and about the bearingassembly 321. A post 372 (FIG. 48) projects downward from the link 370(FIG. 48) along one side edge thereof, with a dependent pin 332 whichpasses lengthwise through the guide channel 324 of a housing-floor boss315 upon movement of the gears and link 370. This transitory anchoragegives a pivot point for the rotatable plate 368.

The driven shaft 320 and its bearingassemblies 322, 323 are retained ina tubular housing insert 346 as a composite unit. This is displaceablebetween the alternate housing recesses 347, 348 (FIG. 46) uponlongitudinal movement of the undercarriage C, which by concurrentlimited rotation of the plate 368 in conjunction with the link 370produces the scissors action of the gear train.

The bevel gear 326carried by the shaft 320 engages another bevel gear327 of a transverse shaft 328 which also carries another gear 329between bearing assemblies 330, 331. In a longitudinal chamber 334 ofthe carriage, formed at one side of and generally parallel to the shaft328, is a longer shaft 335 journalled in axially spaced bearingassemblies 336, 337 and on one end carrying a spur gear 338 in mesh withthe gear 329. Distally it carries a bevel gear 339 which engages a bevelgear 3400f a transverse inward-directed shaft 341. The latter isjoumalled in three bearing assemblies 342, 343, 344 and terminallycarries a bevel gear 345 (FIG. 41) which acts as a drive gear for thepositioning headHZ as described below.

The end of the carriage C which projects the greater amount laterallyfrom the lower telescopic cylinder 42b (left in FIGS. 33, 48) is formedwith a central generally rectangular or cubical recess 350, defined bythree uprightwalls 351, 352, 353, overhung by the rotatable member orhousing 46b and partially by the plate P, with the outer end and bottomof the recess open. The recess forms a socket or pivot mount for apositioning head H2 which carries the ultimate, rotary (thread) cutter(72). The upright side wall 353 is formed with an annular groove orraceway 354 (FIG. 41) surrounding the bearing assembly 344, shaft 341and bevel gear 345 which axially project therethrough from within thecarriage. An annular shoulder 355 of the head H2 is rotatably seated inthe groove 354 with the carriage bevel gear 345 extending through anaxial opening 356 of the head to engage a bevel gear 357 (FIG. 41)carried by a spindle 358 within the body of the head H2. The oppositeside 359 of the head H2 carries an annu- Iar boss which is socketed inthe recess wall 351. A circle of tapped bores 360 in the side of thehead, receive anchoring screws 361 inserted through the outwardopeningbores 362 of the carriage. A cylindrical bore 363 in the side of thecarriage axial to the head H2 gives access for a wrench to engage thehexagonal socket 364 and thus to relocate the head angularly (i.e.,tilt) when the anchoring screws 361 are absent.

With the tiltable head H2, any milling cutter such as thebuttress-thread cutter 72a of FIG. 51 can be positioned within theopen-top bore of a stationary workpiece, and by spiral movement of therotatable housing member 42b in either direction, it cuts a buttressthread. It had not been possible to do this previously. While thetiltable head construction has-been described with particular referenceto this advanced usage, it will be apparent of course that a millingcutter carried by such a head can also perform ordinary milling tasks.Further advantage is obtained by reason of the transverse adjustabilityof the undercarriage. Also, when the head is thus tilted, a cutter oflesser diameter can be employed and thus reduce the cutting forcerequired as compared with a cutter of greater diameter.

I claim:

1. In combination with rotary drive means extending from a stationaryhousing to a rotatable housing and functionally projecting a rotarycutter from the rotatable housing, said housings being connected byextension means adapted to move the rotatable housing in a curved pathrelative to the stationary housing whereby the rotary cutter may cutcurved threads on a workpiece,

the improvement comprising a tiltable positioning head carried by therotatable housing and characterized by a spindle adapted distally toproject said rotary cutter, said positioning head also having lock meansfor anchoring the same at selected tilt positions relative to therotatable housing, and extension gear means connecting the spindle ofthe positioning head with the rotary drive means of the rotatablehousing, whereby the positioning head can be selectively located atdifferent positions

1. In combination with rotary drive means extending from a stationaryhousing to a rotatable housing and functionally projecting a rotarycutter from the rotatable housing, said housings being connected byextension means adapted to move the rotatable housing in a curved pathrelative to the stationary housing whereby the rotary cutter may cutcurved threads on a workpiece, the improvement comprising a tiltablepositioning head carried by the rotatable housing and characterized by aspindle adapted distally to project said rotary cutter, said positioninghead also having lock means for anchoring the same at selected tiltpositions relative to the rotatable housing, and extension gear meansconnecting the spindle of the positioning head with the rotary drivemeans of the rotatable housing, whereby the positioning head can beselectively located at different positions transverse to the axis ofsaid rotary drive shaft and tilted from such positions.
 2. Thecombination of the preceding claim 1 wherein said extension gear meanscomprise a splined shaft transversely carried by the rotatable housingand axially disposed in a longitudinally ribbed bore of a bevel gearwhich is engaged by said rotary drive means, the distal end of saidshaft drivingly engaging the spindle of the tiltable positioning head.3. The combination of the preceding claim 1 wherein said extension meansinclude interchangeable pairs of threadedly engaged guide cylinders,whereby the pitch of an engaged pair of guide cylinders may beduplicated by the threads being cut by the rotary cutter.
 4. Thecombination of the preceding claim 1 wherein said rotatable housingcarries ring gear means and a support axially extensible from thestationary housing carries worm gear means which engages said ring gearmeans, whereby manipulation of the worm gear means moves the rotatablehousing spirally.
 5. A milling assembly of the character described,comprising in combination: a stationary member and a rotatable memberaxially spaced apart by telescopic means connecting the two members forindividual or joint, rotational and axial movement of the rotatablemember, including means for mounting interchangeable pairs of mutuallyrotatably engaging, cylindrical guide sleeve means respectivelysupported by the stationary member and the rotatable member, and thusadapted by their relative rotation to determine the movement of therotatable member relative to the stationary member and when threadedlyengaged to cause a rotary cutter carried by the rotatable member toreproduce the pitch of such threads on a workpiece; a tiltablepositioning head carried by the rotatable member and characterized by aspindle adapted distally to project said rotary cutter, said positioninghead also having lock means for anchoring the same at selected tiltpositions relative to the rotatable member, and lateral extension meansconnecting the spindle of the positioning head with the rotatablemember, whereby the positioning head can be selectively located atdifferent positions transverse to the axis of said rotatable member andtilted from such positions.
 6. An assembly according to claim 5 whereinthe axis of said rotary cutter is positionable substantially opposite tothe direction of extension of said telescopic means.
 7. An assemblyaccording to claim 5 wherein the axis of said rotary cutter ispositionable to conform to thE inclination of the thread being cut. 8.As assembly according to claim 5 wherein the axis of said rotary cutteris positionable substantially throughout a rotational adjustment of360*.